Stock Exchange Listing

Hi,

I'm currently studying CIMA F2 using the Kaplan study texts.

I can't quite get my head around a statement from the book:

"A Stock Exchange Listing makes employee share schemes more accessible".

Please could someone help me on this statement? I understand that employees can be offered onto a share scheme if the entity is listed or unlisted therefore I fail to understand why a listing makes the schemes more accessible.

Many thanks.